CHEOPS (Characterizing Exoplanet Satellite) is a joint Swiss-ESA mission that will realize key investigations of the size and reflectivity of planets that orbit distant stars.
The satellite launched back in December 2019 aboard a big Soyuz rocket, from the northern coast of South America. While we have been on lockdown the last three months, CHEOPS opened its eyes and captured its first photos. Here is what you need to know.
CHEOPS’s Mission is Already a Success
CHEOPS was put in a “Sun-synchronous” orbit, where it stays continuously above the Earth’s line that separates day from night. The satellite uses a 32-centimeter mirror to observe planets as they transit in front of their host stars, and can achieve a precision similar to Kepler.
For one of the brightest stars, CHEOPS can measure the sizes of planets as small as Earth by examining the starlight’s section that is blocked by the planet as it moves in front of the star. The enhanced measurements of planet dimensions help scientists to find out a planet’s density, giving insights into its inner structure and composition. They can also set the key connection between planetary sizes and their masses, which shows us more about the features shared by planets across many systems.
In addition to planet sizes, the satellite can evaluate a planet’s “phase curve,” the contrast in brightness due to the dynamic profile of the planets as it orbits its host star (similar to the Moon’s phases). The phase curve indicates how much light is reflected by the planet, the features of its surface, clouds, and atmosphere. This data, in turn, can help scientists find out more about the conditions that might be at a planet’s surface and under the cloud tops.
Ultimately, since CHEOPS objectives are bright, they’re perfect candidates for advanced observations of their atmosphere using ground-based and space-based telescopes, such as the Extremely Large Telescope, and the James Webb Space Telescope.